Production line quality processes

ABSTRACT

The embodiments described herein relate to methods, systems, and computer program products for improving the product quality of product lots produced on a production line. A quality value for each product lot is determined, and a quality benchmark is established. Each product lot is classified based on the quality benchmark. Product lots that have a quality value meeting the quality benchmark are classified as quality lots, and product lots having a quality value failing to meet the quality benchmark are classified as failing lots. Tools used in the production of the product lots are identified, which includes identifying a set of quality tools and a set of failing tools. Routing of additional product lots is directed by shifting production at least substantially to the set of quality tools.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation patent application claiming thebenefit of the filing date of U.S. patent application Ser. No.13/466,963 filed on May 8, 2012 and titled “Production Line QualityProcesses” now pending, which is hereby incorporated by reference.

BACKGROUND

The present invention relates to production line processes, and moreparticularly to improving lot quality for product lots produced on aproduction line having a plurality of production steps, where at leastsome of the production steps utilize a plurality of individual tools.

A production line typically refers to a set of sequential manufacturingoperations, where each step in the sequence brings the raw materialsubmitted to the production line closer to the form of the desiredmanufactured product. The product of a given production line may be thefinal desired product, or the production line may produce anintermediate material that requires additional manufacturing steps,perhaps by traversing one or more additional production lines, in orderto obtain the desired overall final product.

It is not unusual for a given production line to include multipleproduction steps, and some or all of these production steps may in turnemploy multiple individual tools or workstations, where each tool iscapable of carrying out the desired fabrication for that productionstep. In such cases each individual product lot may take very differentroutes through the production line overall, as each tool in a productionstep that includes multiple tools represents a branch in the flow ofproduct.

While this kind of multiplicity may enhance overall throughput, itpresents particular challenges when product lots begin exhibiting flawsor defects. The time and effort required to troubleshoot the entireproduction line and identify the particular tools and workstations thatare generating the defects represents a substantial loss in valuableproduction time.

BRIEF SUMMARY

The present disclosure is directed to methods, systems, and computerprograms for improving product lot quality for product lots produced bya production line, so that both the quality of the product and theoverall throughput of the production line are maintained.

According to one aspect, a method is provided for improving productquality. The method producing product lots via one or more productionsteps. A quality value for each product lot is determined, and a qualitybenchmark is established. Each product lot is classified based on thequality benchmark. Product lots that have a quality value meeting thequality benchmark are classified as quality lots, and product lotshaving a quality value failing to meet the quality benchmark areclassified as failing lots. Tools used in the production of the productlots are identified, which includes identifying a set of quality toolsand a set of failing tools. Routing of additional product lots isdirected by shifting production at least substantially to the set ofquality tools.

According another aspect, a production system is provided to improveproduct quality. The system includes a production line having one ormore production steps to produce product lots. The system furtherincludes a processor in communication with a memory storage device, andconfigured to direct each product lot to an individual tool at eachproduction step, and to record each tool utilized to produce eachproduct lot. The system further includes a quality feedback input is incommunication with the processor to transmit a quality value of eachproduct lot to the processor. The system further includes a programhaving a plurality of instructions stored in the memory storage deviceand executable by the process to classify each product based on aquality benchmark. Product lots that have a quality value meeting thequality benchmark are classified as quality lots, and product lots thathave a quality value failing to meet the quality benchmark areclassified as failing lots. The program has further instructions toidentify one or more tools used in the production of the lots, includinginstructions to identify a set of quality tools and a set of failingtools. The set of quality tools includes one or more tools used toproduce the quality lots, and the set of failing tools includes one ormore tools used to produce the failing lots. The program has furtherinstructions to direct routing of additional product lots by shiftingproduction at least substantially to the set of quality tools.

According to yet another aspect, a computer program product is providedto improve product quality. The computer program product includes acomputer-readable storage medium having computer readable code embodiedtherewith. The program code is executable by a processor to produce aplurality of product lots via one or more production steps. A qualityvalue for each product lot is determined, and a quality benchmark isestablished. Each product lot is classified based on the qualitybenchmark. Product lots that have a quality value meeting the qualitybenchmark are classified as quality lots, and product lots having aquality value failing to meet the quality benchmark are classified asfailing lots. Tools used in the production of the product lots areidentified, which includes identifying a set of quality tools and a setof failing tools. Routing of additional product lots is directed byshifting production at least substantially to the set of quality tools.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a flowchart depicting a method of improving lot quality for aproduction line according to an exemplary embodiment of the presentinvention.

FIG. 2A represents the determination of a rate of failure within a givenproduct lot. FIG. 2B depicts the selection of a set of product lots thathave passed an established quality benchmark.

FIG. 3A is a schematic depiction of the individual tools utilized ateach of the multiple steps of a production line, according to anexemplary embodiment of the invention. FIG. 3B depicts theidentification of the tools identified as producing product lots thatexceed the established quality benchmark. FIG. 3C depicts theidentification of tools identified as failing to produce product lotsthat exceed the established quality benchmark. FIG. 3D depicts theidentification of suspect tools for additional evaluation.

FIG. 4A is a schematic depiction of the individual tools utilized ateach of the multiple steps of a production line, according to anexemplary embodiment of the invention. FIG. 4B depicts theidentification of tools identified as failing to produce product lotsthat exceed the established quality benchmark. FIG. 4C depicts theidentification of the tools identified as producing product lots thatexceed the established quality benchmark. FIG. 4D depicts theidentification of tools that are not identified as failing to producequality product lots, or that are identified as quality tools.

FIG. 5 is a pictorial representation of an example of a computer systemin which illustrative embodiments may be implemented.

FIG. 6 is a block diagram of an example of a computer in whichillustrative embodiments may be implemented.

DETAILED DESCRIPTION

With reference now to flowchart 10 of FIG. 1, one embodiment of thepresent invention may include a method of improving product lot qualityincluding at least a) producing a plurality of product lots usingdifferent combinations of tools at 12; b) determining quality values forthe produced production lots at 13; c) establishing a quality benchmarkfor the product lots at 14; d) identifying those product lots that meetthe established quality benchmark at 16; e) identifying the tools usedin the production of any of the identified quality products at 18; andf) producing additional product lots by shifting production at leastsubstantially to the set of identified quality tools at 20.

By executing actions 12-20 of flowchart 10, the reduced quality of someof the products being produced by the production line may be addressed.By correlating product lots that exhibit adequate qualitycharacteristics with the tools that were used to manufacture thosequality product lots, production may be shifted to the quality tools inorder to improve overall product quality, even when the specific causeor causes of an observed decrease in quality may be unknown.Advantageously, the corrective shift to quality tools may be implementedwithout decreasing the production line throughput, or failing to meetestablished production quotas. In one embodiment of the invention, theshift to quality tools, with concomitant increase in product quality, isachieved without halting the operation of the production line. That is,the manufacturing process may continue as an ongoing process whilepermitted pathways through the production line are adjusted to shiftproduction to quality tools.

The method described by actions 12-20 may be extended through thefurther performance of actions 22-28 of flowchart 10. These additionalactions include g) identifying product lots that failed to meet theestablished quality benchmark at 22; h) identifying the tools used inthe production of the identified failing product lots at 24; identifyingthose failing tools that were not identified as quality tools in actione), creating a list of tools suspected of being a source of decreasedquality at 26; and i) evaluating the listed suspect tools in order todetermine one or more sources of decreased quality, and therefore afailure to meet the quality benchmark, that may have been caused by oneor more suspect tools, at 28.

After actions 12-20, which shift production to identified quality tools,for example when a decrease in product lot quality is observed, it mayoften prove useful to try to determine the factors that may havecontributed to the observed decrease in quality. Simply identifying alltools used to produce failing product lots, as done at 24 of flowchart10, may not be sufficient because some production lines includeproduction steps that employ only a single workstation for all productlots manufactured. That is, every product lot, whether it passes orfails the established quality benchmark, would have been routed throughthe singular workstation, creating a workflow bottleneck of sorts. Itmay therefore be necessary to first identify those tools used to createfailing product lots, but then to additionally remove from that set ofidentified tools any of the tools that were also identified as producingquality product lots. This may prove helpful when troubleshootingpotential reasons for the observed decrease in quality, by narrowingdown potential sources of failure to a smaller subset of tools.

FIGS. 2A-2B help illustrate the application of a quality value tomultiple product lots, as well as the identification of quality productlots meeting a quality benchmark, according to an exemplary embodimentof the invention. In particular, FIG. 2A depicts a plot of the failurerates for each product lot in a selection of multiple product lots. Itshould be appreciated that the definition of a failure for theindividual products may be independent of the quality value for theoverall product lot. For example, as reflected in FIG. 2A, a productfailure may represent the failure of an operational test that may beperformed on each product.

FIG. 2B depicts the selection of a number of a subset of product lotsexhibiting failure rates below an established quality benchmark. Thequality benchmark for the product lot may correspond to a maximumpermitted percentage of individual failing products within the productlot as a whole. As depicted in FIG. 2B, a quality benchmarkcorresponding to a product failure rate of 2% has been set, as indicatedby the corresponding dashed line. In this example, a quality benchmarkis selected as a value included in the range of quality valuesdetermined for the product lots, i.e. about 0.5%-6.0%. Specifically,product lots 10013-10020 are shown to exhibit a failure rate of lessthan 2%. In the illustrative example of FIG. 2B, product lots10013-10020 are selected to correspond to identified quality productlots, as evidenced by rectangle 29 which highlights the low failurerates for that grouping of product lots.

It should be noted that in some examples the set of identified qualityproduct lots need not be grouped adjacent to one another, as shown inFIG. 2B. For example, product lot identifiers may have only arbitrarysignificance, and therefore adjacent product lots may not reflectproduction on the same or adjacent workstations. In an alternativeaspect of the invention, the identification of quality product lots isbased on passing the established benchmark, and every product lot whichpasses the benchmark is therefore included in the set of identifiedquality product lots. In reference to FIG. 2B, that methodology wouldalso result in the inclusion of product lots 10027 and 10035 withproduct lots 10013-10020 as identified quality product lots.

Alternatively, or in addition, the identified set of quality productlots may be in part selected by virtue of being produced within aselected time frame, or for example by including only those product lotsin the set of identified quality product lots that both a) pass thequality benchmark, and b) share a selected degree of overlap in theparticular tools used during their manufacture. These methods, amongothers, may be used to define what is and what is not included in theset of quality product lots.

FIG. 3A schematically depicts a production line that includes productionsteps I-VII. For each production step, the individual tools availablefor carrying out that step are indicated by boxes 30A-36A. That is,production step I employs two individual tools, 30A and 30B, whileproduction step II employs four individual tools, 31A-31D. Productionsteps IV and VII each employ only a single individual tool, 33A and 36Arespectively. For the purposes of the presently illustrated example, theselection of a particular individual tool for a given production step israndom for a given product lot. It should be appreciated, however, thatactual production lines may employ alternative selection schemes, whichmay reflect the effect of physical proximity between sequential tools,or incorporate safeguards to minimize the overuse of any particularindividual tool to avoid excessive and unbalanced wear. The method ofselecting the tool used for an individual product lot at any givenproduction step may therefore be biased in one way or another. Suchbiases may typically be taken into consideration by careful tailoring ofthe selection criteria used to identify the set of quality product lots.

FIG. 3B illustrates an exemplary identification of the tools used toprepare identified quality product lots, once the identification ofquality product lots has been performed (see FIG. 2B, for example).Tools determined to have been used to prepare a quality product lot(tools 30B, 31B, 31C, 32C, 33A, 34B, 34D, 35A, 35B, and 36A) are shownas bold boxes, while the remaining tools of the production line areshown in dashed outline.

As set out at action 20 of FIG. 1, by producing additional product lotsusing at least substantially the set of identified quality tools, thequality of subsequent product lots should be improved. Importantly, auser need not know why the tools that produced the quality product lotsidentified in FIG. 2B are quality tools, or what the causes of reducedquality when using other tools might be. The user need only identifythese quality tools and switch production to the identified tools inorder to obtain the corresponding benefit of enhanced product quality.

However as set out at 22 of FIG. 1, it may also be desirable to identifythose tools that have been used in the production of identified failingproduct lots. The criteria for identifying such product lots may vary.For example, with reference to FIG. 2B, failing product lots maycorrespond to all product lots other than lots 10013-10020.Alternatively, all product lots exhibiting a failure rate greater thanthat selected for the quality benchmark (in this case 2.0%) may beidentified as failing product lots. In yet another aspect of theinvention, another even lower quality benchmark value may be set inorder to identify failing product lots. For example, with reference toFIG. 2B, by setting the failure benchmark at 5.0%, product lots 10009,10010, 10025, and 10029 would be identified as failing product lots.

Once the set of failing product lots has been identified, thecorresponding individual tools used to produce the failing product lotsare identified, as set out at 24 in FIG. 1. With reference to FIG. 3C,those tools used to produce identified failing product lots are shownwith cross-hatching (tools 30B, 31A, 31C, 32B, 33A, 34C, 34D, 35A, and36A). However, as discussed previously production steps IV and VII eachemploy a single tool. As a result, these tools are necessarily employedin the manufacture of every product lot that is manufactured using theproduction line, whether it exhibits high quality or low quality. It istherefore impossible to avoid the identification of tools 33A and 36A asbeing used to prepare failing product lots. However, if a tool that isidentified as failing tool is also identified as a quality tool, it maybe disregarded when identifying failing tools. If such a tool were thesource of poor product quality and/or product failure, then it would beexpected that all product lots produced by the production line wouldfail the quality benchmark.

Removing those tools identified as quality tools from the set of toolsidentified as failing tools, as set out at 26 of FIG. 1, leaves onlythose tools that are likely to be a source of poor quality and/orproduct failure. With respect to FIG. 3D, these suspect tools areidentified with a bold outline, while all other tools are shown indashed lines. The identification of such suspect tools (tools 31A, 32B,and 34C) allows them to be taken off-line in order to be examined andevaluated in hopes of determining one or more causes of poor qualityand/or product failure, so that it may be corrected.

By virtue of quickly identifying those tools that are likely to bereliable, and shifting production to those quality tools, the output ofthe production line may be maintained and the quality of the resultingproduct improved. At the same time, by further identifying likelysuspect tools, technicians and operators may quickly devote time andenergy to the tools most likely to be the source of poor qualityproduct. In the hypothetical example of FIGS. 3A-3D, even though theproduction line employs eighteen individual tools, by carrying out theidentification and selection processes of the present invention, onlythree tools are marked as likely sources of the observed decrease inquality. Advantageously, this analysis is may be validly performedindependently of the type of product being manufactured, the type offabrication being carried out, or the types of individual tools beingused.

Also as shown in flowchart 10 of FIG. 1, an alternative embodiment ofthe present invention may include a method of improving product lotquality including at least a) producing a plurality of product lotsusing different combinations of tools at 12; b) determining a qualityvalue for the produced product lots at 13; c) establishing a qualitybenchmark for the product lots at 14; d) identifying those product lotsthat fail to meet the established quality benchmark at 40; e)identifying the tools used in the production of any of the identifiedfailing products at 42; f) identifying product lots that meet theestablished quality benchmark at 44; g) identifying those tools used inthe production of any identified quality product lots at 46; and h)producing additional product lots by shifting production at leastsubstantially to tools those tools that were not identified as failingtools, and to tools that at least substantially away from those toolsidentified as failing tools, excepting those that are not alsoidentified as quality tools at 48.

The two disclosed methods are similar, but where the previouslydiscussed method emphasized a shift in production to tools that shouldimmediately enhance product quality, and then optionally identifyingthose tools most likely to be a source of quality failure, the alternatemethod emphasizes identifying all potentially suspect tools, andshifting production away from those tools.

These differences may be visualized with reference to FIGS. 4A-4D. FIG.4A schematically depicts the production line of FIG. 3A, includingproduction steps I-VII, and individual tools 30A-36A. FIG. 4Billustrates an exemplary identification of the tools used to prepareproduct lots that have failed the established quality benchmark, as setout at 42 of FIG. 1. Tools determined to have been used to prepare afailing product lot (tools 30B, 31A, 31C, 32B, 33A, 34C, 34D, 35A, and36A) are shown with crosshatching.

FIG. 4C depicts the identification of the tools used in the productionof any product lots identified as passing the established qualitybenchmark, set out at 46 of FIG. 1. Those tools that produced qualityproduct lots are shown with a bold outline (tools 30B, 31B, 31C, 32C,33A, 34B, 34D, 35A, 35B, and 36A), the remaining tools are shown indashed outline. It should be apparent that some overlap exists betweenthe set of identified failing tools and identified quality tools,specifically tools 30B, 31C, 33A, 34D, 35A, and 36A are both identifiedas failing tools and quality tools.

In order to improve overall production quality, production is thenshifted so that additional product lots are manufactured at leastsubstantially without using identified failing tools that are not alsoidentified quality tools, as set out at 48 of FIG. 1. With respect toFIG. 4D, this means that production is shifted away from those toolsshown in dashed outline (tools 31A, 32B, and 34C).

By quickly identifying those tools that are likely to be least reliable,and shifting production to those tools that are most likely to producequality product lots, the output of the production line may bemaintained and the quality of the resulting product improved. Again, thedisclosed method is substantially independent of the type of product,type of fabrication operation, or type of individual tool used in theproduction line.

It should be readily apparent that the methods disclosed herein areapplicable to the manufacture of any of a wide variety of products,employing a variety of disparate production techniques. However, in oneembodiment of the present invention the methods disclosed herein may beused in particular to improve the product lot quality for semiconductorchip packages. In particular, the present methods may enhance thequality of fabricated semiconductor chip assemblies where the fabricatedsemiconductor chip is mounted in a chip package. The chip package may bea single chip package (such as a plastic carrier, with leads that areconfigured to be affixed to a motherboard or other higher level carrier)or a multichip package (such as a ceramic carrier that has either orboth surface interconnections or imbedded interconnections).

The manufacture of semiconductor chip packages is typically a multi-stepprocess, and may include from one to more than ten individual tools atany given production step in the production line, depending upon theindividual tool capacities and their speed of operation. The productionline may additionally include one or more optical quality inspections.The progression of a given product lot through a production line may bea strictly manual process, or one or more aspects of the production lineoperation may be automated.

Where the presently disclosed methods are utilized to improve productquality in semiconductor chip package manufacture, the individuallyproduction steps for a given production line may include one or more ofoptical inspections, wafer grinding, wafer polishing, wafer taping,wafer detaping, wafer mounting, wafer dicing, UV erasing, dieattachment, epoxy curing, plasma cleaning, wire bonding, molding, modulemarking, module curing, chip mounting, reflow soldering, flux cleaning,singulation, and dry packing, in any suitable order.

In one embodiment of the invention, the quality of the manufacturedsemiconductor chip packages is functionally tested. That is, one or moreaspects of the chip package are evaluated to determine if each packageis functioning properly. When present, it may be particularlyadvantageous to test the portion of the chip that includes a PhaseLocked Loop (PLL), for a variety of reasons that may includeaccessibility, ease of testing, lack of ambiguity in test results, amongothers. Additionally, the PLL portion of a chip carrier may be moreprone to the kinds of damage caused by electrostatic discharge, or ESD,a significant source of failure in chip package manufacture.

In one aspect of the invention, identified suspect tools (as set out at26 of FIG. 1, and shown in FIG. 3D) may be taken off-line in order to beanalyzed for possible sources of ESD damage to the manufactured chips,while production is shifted at least substantially to identified qualitytools, so that production is not interrupted.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a method, a computer system, or computerprogram product. Accordingly, aspects of the present invention may takethe form of an entirely hardware embodiment, an entirely softwareembodiment (including firmware, resident software, micro-code, etc.) oran embodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF cable, etc., or any suitablecombination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

With reference now to the figures and in particular with reference toFIGS. 5-6, exemplary diagrams of data processing environments areprovided in which illustrative embodiments may be implemented. It shouldbe appreciated that FIGS. 5-6 are only exemplary and are not intended toassert or imply any limitation with regard to the environments in whichdifferent embodiments may be implemented. Many modifications to thedepicted environments may be made.

FIG. 5 depicts a pictorial representation of a computer system,indicated generally at 100, and including a network of computers inwhich illustrative embodiments may be implemented. Computer system 100may contain a network 102, which is the medium used to providecommunications links between various devices and computers connectedtogether within computer system 100. Network 102 may includeconnections, such as wire, wireless communication links, or fiber opticcables.

In the depicted example, a server 104 and a server 106 may connect tonetwork 102 along with a storage unit 108. In addition, a first clientcomputer 110, a second client computer 112, and a third client computer114 may connect to network 102. Client computers 110, 112, and 114 maybe, for example, personal computers or network computers. In thedepicted example, server 104 may provide data, such as boot files,operating system images, and/or software applications to clientcomputers 110, 112, and 114. Client computers 110, 112, and 114 areclients to server 104 in this example. Computer system 100 may includeadditional servers, clients, and other devices not shown, or may includefewer devices than those shown.

In the depicted example, network 102 may be or may include the Internet.Computer system 100 also may be implemented with a number of differenttypes of networks, such as for example, an intranet, a local areanetwork (LAN), or a wide area network (WAN). FIG. 5 is intended as anexample, and not as an architectural limitation for the differentillustrative embodiments. For example, embodiments of the presentinvention are capable of being implemented in conjunction within a cloudcomputing environment.

With reference now to FIG. 6, a block diagram of a data processingsystem is shown in which illustrative embodiments may be implemented.Data processing system 200 is an example of a computer, such as server104 or client computer 110 in FIG. 2, in which computer-usable programcode or instructions implementing the processes may be located for theillustrative embodiments. In this illustrative example, data processingsystem 200 includes communications fabric 202, which providescommunications between a processor unit 204, a memory 206, a persistentstorage 208, a communications unit 210, an input/output (I/O) unit 212,and display 214. In other examples, a data processing system may includemore or fewer devices.

Processor unit 204 may serve to execute instructions for software thatmay be loaded into memory 206. Processor unit 204 may be a set of one ormore processors or may be a multi-processor core, depending on theparticular implementation. Further, processor unit 204 may beimplemented using one or more heterogeneous processor systems in which amain processor is present with secondary processors on a single chip. Asanother illustrative example, processor unit 204 may be a symmetricmulti-processor system containing multiple processors of the same type.

Memory 206 and persistent storage 208 are examples of storage devices. Astorage device is any piece of hardware that is capable of storinginformation either on a temporary basis and/or a permanent basis. Memory206, in these examples, may be, for example, a random access memory orany other suitable volatile or non-volatile storage device. Persistentstorage 208 may take various forms depending on the particularimplementation. For example, persistent storage 208 may contain one ormore components or devices. For example, persistent storage 208 may be ahard drive, a flash memory, a rewritable optical disk, a rewritablemagnetic tape, or some combination of the above. The media used bypersistent storage 208 also may be removable. For example, a removablehard drive may be used for persistent storage 208.

Communications unit 210, in these examples, provides for communicationswith other data processing systems or devices. For example,communications unit 210 may be a network interface card. Communicationsunit 210 may provide communications through the use of either or bothphysical and wireless communications links.

Input/output unit 212 allows for input and output of data with otherdevices that may be connected to data processing system 200. Forexample, input/output unit 212 may provide a connection for user inputthrough a keyboard and mouse. Further, input/output unit 212 may sendoutput to a printer. Display 214 displays information to a user.

Instructions for the operating system and applications or programs arelocated on persistent storage 208. These instructions may be loaded intomemory 206 for execution by processor unit 204. The processes of thedifferent embodiments may be performed by processor unit 204 usingcomputer implemented instructions, which may be located in a memory,such as memory 206. These instructions are referred to as program code,computer-usable program code, or computer-readable program code that maybe read and executed by a processor in processor unit 204. The programcode in the different embodiments may be embodied on different physicalor tangible computer-readable media, such as memory 206 or persistentstorage 208.

Program code 216 may be located in a functional form on acomputer-readable media 218 that is selectively removable and may beloaded onto or transferred to data processing system 200 for executionby processor unit 204. Program code 216 and computer-readable media 218form computer program product 220 in these examples. In one example,computer-readable media 218 may be in a tangible form, such as, forexample, an optical or magnetic disc that is inserted or placed into adrive or other device that is part of persistent storage 208 fortransfer onto a storage device, such as a hard drive that is part ofpersistent storage 208. In a tangible form, computer-readable media 218also may take the form of a persistent storage, such as a hard drive, athumb drive, or a flash memory that is connected to data processingsystem 200. The tangible form of computer-readable media 218 is alsoreferred to as computer-recordable storage media. In some instances,computer-recordable media 218 may not be removable.

Alternatively, program code 216 may be transferred to data processingsystem 200 from computer-readable media 218 through a communicationslink to communications unit 210 and/or through a connection toinput/output unit 212. The communications link and/or the connection maybe physical or wireless in the illustrative examples. Thecomputer-readable media also may take the form of non-tangible media,such as communications links or wireless transmissions containing theprogram code. The different components illustrated for data processingsystem 200 are not meant to provide architectural limitations to themanner in which different embodiments may be implemented. The differentillustrative embodiments may be implemented in a data processing systemincluding components in addition to or in place of those illustrated fordata processing system 200. Other components shown in FIG. 6 can bevaried from the illustrative examples shown. As one example, a storagedevice in data processing system 200 is any hardware apparatus that maystore data. Memory 206, persistent storage 208, and computer-readablemedia 218 are examples of storage devices in tangible forms.

In another example, a bus system may be used to implement communicationsfabric 202 and may be comprised of one or more buses, such as a systembus or an input/output bus. Of course, the bus system may be implementedusing any suitable type of architecture that provides for a transfer ofdata between different components or devices attached to the bus system.Additionally, a communications unit may include one or more devices usedto transmit and receive data, such as a modem or a network adapter.Further, a memory may be, for example, memory 206 or a cache such asfound in an interface and memory controller hub that may be present incommunications fabric 202.

The methods of the present invention, as described above, may beexecuted using a production system. According to one embodiment of thepresent invention, the production system includes a production line fora product that has a plurality of production steps, where at least someof the production steps utilize a plurality of individual tools; aprocessor, configured to direct each product lot to an individual toolat each production step, and to record each tool utilized to produceeach product lot; a memory storage device coupled to the processor; aquality feedback input, configured to transmit a quality value for eachcompleted product lot to the processor; and a program stored in thememory storage device. The stored program itself includes pluralinstructions that are executable by the processor to: receive dataidentifying the individual tools used to produce each of a plurality ofidentified product lots; identify completed product lots that have apassing quality value; identify tools used in the production ofidentified quality product lots; and direct the routing of subsequentproduct lots to individual tools at each production step that have beenidentified as quality tools.

Where a production line utilizes a processor to direct the routing ofproduct lots to individual tools, the directed routing process maysimply include the identification of an appropriate tool for a givenproduct lot, so that the product lot may be individually and/or manuallydelivered to the identified tool. This identification may occur via thegeneration of an electronic or paper report, or by way of graphicaldirection provided via one or more displays or monitors, among othermethods. Alternatively, or in addition, the directed routing process mayinclude one or more automated steps, such as the delivery of a givenproduct lot to the identified tool by conveyer or other means that canbe directly controlled by the processor. For any given production line,product lots may be directed between the individual production stepsmanually, by automated processes, or by any combination of manual andautomated processes.

In one embodiment of the invention, the production system is directed tothe manufacture of semiconductor chip packages. In this embodiment theplurality of production steps in the production line may include one ormore of optical inspection, wafer grinding, wafer polishing, wafertaping, wafer detaping, wafer mounting, wafer dicing, UV erasing, dieattachment, epoxy curing, plasma cleaning, wire bonding, molding, modulemarking, module curing, chip mounting, reflow soldering, flux cleaning,singulation, and dry packing.

In an alternative embodiment of the present invention, the invention mayinclude a computer program product for improving lot quality for productlots produced on a production line having a plurality of productionsteps, where at least some of the production steps utilize a pluralityof individual tools, the computer program product including a pluralityof computer-executable instructions stored on a computer-readablemedium, where the instructions are executable by a server to: receivedata identifying the individual tools used to produce each of aplurality of identified product lots; receive data identifying thequality value of each identified product lot; compare the quality ofeach identified product lot to a threshold quality value; identify alltools that were used to produce identified product lots exceeding thethreshold quality value; and direct the production of additional productlots to those tools identified as producing product lots exceeding thethreshold quality value.

In yet another embodiment of the invention, the computer program productof the present invention may further include instructions executable bythe server to: identify all tools that were used to produce product lotsfailing to meet the threshold quality value; and exclude from theidentified failing tools any tools also identified as producing productlots exceeding the threshold quality value; identify the remainingfailing tools as potential sources of poor product lot quality; anddirect the production of additional product lots to those toolsidentified as producing product lots exceeding the threshold qualityvalue.

The computer program product of the present invention may furtherinclude instructions executable by the server to: identify all toolsthat were used to produce product lots failing to meet the thresholdquality value; exclude from the identified failing tools any tools alsoidentified as producing product lots exceeding the threshold qualityvalue; and identify the remaining failing tools as potential sources ofpoor product lot quality.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the various embodiments of the present invention has beenpresented for purposes of illustration, but is not intended to beexhaustive or limited to the embodiments disclosed. Many modificationsand variations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A method of improving lot quality for productlots produced on a production line, the method comprising: producing aplurality of product lots via one or more production steps; determininga quality value for each product lot; establishing a quality benchmark;classifying each product lot based on the quality benchmark comprisingperforming a functional test, including functionally testing a phaselocked loop of the each product lot to determine a failure rate for eachproduct lot, wherein product lots that have a quality value meeting thequality benchmark are classified as quality lots, and wherein productlots that have a quality value failing to meet the quality benchmark areclassified as failing lots; identifying one or more tools used in theproduction of the product lots, including identifying a set of qualitytools and a set of suspect tools, wherein the set of quality toolscomprises one or more tools used to produce the quality lots, and theset of suspect tools comprises one or more tools used to produce thefailing lots; directing routing of additional product lots by shiftingproduction at least substantially to the set of quality tools; andevaluating the set of suspect tools to determine a cause of failurecontributed by the use of the suspect tools.
 2. The method of claim 1,wherein producing additional product lots further comprises producingproduct lots having improved quality.
 3. The method of claim 1, whereinthe additional lots are produced without interrupting the productionline and maintaining a desired overall throughput for the productionline.
 4. The method of claim 1, wherein the product lots comprisesemiconductor chip packages.
 5. The method of claim 4, wherein theproduction steps comprise one or more of optical inspection, wafergrinding, wafer polishing, wafer taping, wafer detaping, wafer mounting,wafer dicing, UV erasing, die attachment, epoxy curing, plasma cleaning,wire bonding, molding, module marking, module curing, chip mounting,reflow soldering, flux cleaning, singulation, and dry packing.
 6. Themethod of claim 4, wherein evaluating the listed suspect tools comprisesdetermining that one or more semiconductor chip package failures arerelated to electrostatic discharge-related damage.
 7. The method ofclaim 1, further comprising identifying the set of suspect tools,wherein the set of suspect tools comprises one or more failing toolsthat are separate from the set of quality tools.
 8. The method of claim1, wherein establishing the quality benchmark comprises establishing amaximum acceptable failure rate, and wherein classifying the productlots comprises: determining a failure rate for each product lot;comparing the determined failure rate to the maximum acceptable failurerate; classifying each product lot having a determined failure rate lessthan the maximum acceptable failure rate as a quality lot; andclassifying each product lot having a determined failure rate exceedingthe maximum acceptable failure rate as a failing lot.
 9. The method ofclaim 1, further comprising removing from the set of suspect tools anytools identified as producing quality lots.
 10. A production systemcomprising: a production line, the production line having one or moreproduction steps to produce product lots; a processor in communicationwith a memory storage device, the processor configured to direct eachproduct lot to an individual tool at each production step, and to recordeach tool utilized to produce each product lot; a quality feedback inputin communication with the processor, the quality feedback input totransmit a quality value of each product lot to the processor; a programhaving a plurality of instructions stored in the memory storage deviceand executable by the processor to: classify each product based on aquality benchmark comprising performing a function test, including tofunctionally test a phase locked loop of each product lot to determine afailure rate for each product lot, wherein product lots that have aquality value meeting the quality benchmark are classified as qualitylots, and wherein product lots that have a quality value failing to meetthe quality benchmark are classified as failing lots; identify one ormore tools used in the production of the lots, including instructions toidentify a set of quality tools and a set of suspect tools, wherein theset of quality tools comprises one or more tools used to produce thequality lots, and the set of suspect tools comprises one or more toolsused to produce the failing lots; direct routing of additional productlots by shifting production at least substantially to the set of qualitytools; and evaluate the set of suspect tools to determine a cause offailure contributed by the use of the suspect tools.
 11. The system ofclaim 10, wherein producing additional product lots further comprisesthe production line to produce product lots having improved quality. 12.The system of claim 11, wherein additional product lots are producedwithout interrupting the production line and maintaining a desiredoverall throughput for the production line.
 13. The system of claim 10,wherein the product lots comprise semiconductor chip packages.
 14. Thesystem of claim 13, wherein the production steps comprise one or more ofoptical inspection, wafer grinding, wafer polishing, wafer taping, waferdetaping, wafer mounting, wafer dicing, UV erasing, die attachment,epoxy curing, plasma cleaning, wire bonding, molding, module marking,module curing, chip mounting, reflow soldering, flux cleaning,singulation, and dry packing.
 15. The system of claim 10, whereinevaluating the listed suspect tools comprises instructions to determinethat one or more semiconductor chip failures are related toelectrostatic discharge-related damage.
 16. The system of claim 10,further comprising instructions to identify the set of suspect tools,wherein the set of suspect tools comprises one or more failing toolsthat are separate from the set of quality tools.
 17. The system of claim10, wherein establishing the quality benchmark comprises instructions toestablish a maximum acceptable failure rate, and wherein classifying theproduct lots further comprises instructions to: determine a failure ratefor each product lot; and compare the determined failure rate to themaximum acceptable failure rate; classify each product lot having adetermined failure rate less than the maximum acceptable failure rate asa quality lot; and classify each product lot having a determined failurerate exceeding the maximum acceptable failure rate as a failing lot. 18.A computer program product comprising a computer-readable storage devicehaving a plurality of computer readable program code embodied therewith,the program code executable by a processor to: produce a plurality ofproduct lots via one or more production steps; determine a quality valuefor each product lots; establish a quality benchmark; classifying eachproduct lot based on the quality benchmark comprising performing afunction test, including to functionally test a phase locked loop ofeach product lot to determine a failure rate for each product lot,wherein product lots that have a quality value meeting the qualitybenchmark are classified as quality lots, and wherein product lots thathave a quality value failing to meet the quality benchmark areclassified as failing lots; direct the production of additional productlots by shifting product at least substantially to the set of qualitytools; and evaluate a set of suspect tools to determine a cause offailure contributed by the use of the suspect tools.